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hw Nw ww United States Patent O 3,506,354 COPIER La Vern L. Linse, White Bear Township, Ramsey County,

Minn., assignor to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware Filed Dec. 22, 1967, Ser. No. 693,010 Int. Cl. G03b 27/22, 27/30 U.S. Cl. 355-106 5 Claims ABSTRACT F THE DISCLOSURE This invention relates to the copying of printed documents, sketches, and other graphic originals, and has particular reference to simplified apparatus for making such copies by processes involving light-exposure and heat-development and employing a single source of energy.

Copy-sheet materials and processes are known for making copies of graphic originals by iirst exposing a lightsensitive sheet to a light-image and then developing a visible image by heating. A well-known older system employs sheet materials having light-sensitive diazo coatings and converts the non-light-struek portions of the diazo compound to an azo dye by reaction with couplers in the presence of an alkaline environment obtained on heating. A more recent and widely accepted system is described in U.S. Patent No. 3,094,417; it operates by desensitizing the background areas of an intermediate sheet under reilex exposure, and then heating the sheet in contact with a receptor or copy-sheet to develop a visible image.

The present invention provides apparatus which is particularly useful in making copies of graphic originals by the latter method, using the light-sensitive intermediate and the heat-sensitive composite of intermediate and copy-sheet as described in said Patent No. 3,094,417. In one aspect, the invention makes possible an apparatus of such simplicity of construction as to be useful as a toy or for economical large-scale instructional use in the copying of written or printed matter.

In the drawing,

FIGURES 1-3 represent left end, side, and right end elevations respectively of one exemplary form of apparatus, with portions cut away to show detail, and

FIGURES 4-6 are similar views of a somewhat more sophisticated form of apparatus.

The apparatus of FIGURES 1-3 comprises a rounded heat-conductive open-faced smooth-surfaced shell 11, here shown removably supported on a base 12 which may for simplicity be a desk-top or table-top. The ends 13, 14 of the shell 11 are centrally perforated to accept bearings 15, 16 respectively. All or part, as required, of the inner surface of the rounded portion of the shell 11 is provided with a light-absorptive heat-conductive coating 17.

An open trough-like reiector 18 supported on centrally perforated circular end discs 19, 20I is suspended from the bearings 15, 1'6. A tubularV lamp 21 is suspended along the same axis between the bearing and a socket 22 passing through the tubular bearing 16. A cable 23 connects the socket 22 and the lamp 21 to a suitable source of power.

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A handle 24 is attached to the tubular bearing 16 and may be rotated between stops 25 and 26 on the outer face of end 14 and between suitable indicia or legends such as D (for develop) and E (for expose) as indicated.

The lamp 21 extends along the entire length of the shell 11, being conveniently supported by the terminal sockets 15, 22, to provide good uniformity of radiation over the entire exposure and development areas. The reflective end discs assist in assuring uniform radiation. Other sources of radiation may be substituted for the lamp 21; for example a much shorter lamp may be supported from a suitable socket or sockets mounted centrally between the ends of the shell, e.g. on suitable tubular supports extending inwardly therefrom. The surface of the reflector 18 and discs 19, 20 may be made diffusereflecting or may be suitably shaped or otherwise modied to improve the uniformity of illumination at the exposure station if found desirable. Similarly, the coating 17 may be arranged in a pattern designed for most effective absorption in areas receiving least amounts of incident radiant energy whereby to provide essentially uniform heating over the entire development.

In operation, a printed page or other graphic original of which a copy is desired is placed, printed side up, on the base 12 and is covered with a photosensitive intermediate sheet. The apparatus is placed over the area to be copied, the edges of the shell 11 helping to smooth the two sheets. If desired, a resiliently compressible panel may be placed beneath, and a thin pane of transparent glass or plastic may be inserted over the sheets to provide additional smoothness. The handle is moved to the expose position, raising the reflector 18 to a position opposite the open face, and the lamp is turned on. After a suitable exposure interval, the reflector is swung to the opposite position, i.e. across the open face, by moving the handle to the develop position. The apparatus is lifted from the sheets, the intermediate is removed and placed against a sheet of copy-paper, and the composite is held under tension across the rounded top of the shell 11 which by that time has become at least moderately heated by absorption of the radiant energy. The heating promotes the development of a visible image on the copypaper, which image can be seen through the semi-transparent intermediate. The composite is then removed and the intermediate is discarded.

The apparatus 40 of FIGURES 4-6 comprises a base 41 and end supports 42, 43 centrally perforated and tted with tubular bushings 44, 45. A bridge 46 supports a socket 47 within bushing 44, and a socket 48 is supported within bushing 45. A tubular lamp 49 extends between the sockets 47, 48, being connected to a source of power by means of a cable 50.

,Rotatably suspended from the bushings 44, 45 are two end discs 51, 52 which in turn support a two-piece cylinder 53 having a transparent portion 54 and an opaque heat-conductive portion 55, the latter desirably being provided with an interior radiation-absorptive coating 56. A spring-loaded stop 57 holds the disc 52 with either the transparent half or the opaque half of the cylinder 53 in the top position, by interaction with suitably located pockets 58.

A trough-like reflector 59 is supported within the cylinder 53 from semicircular end pieces 60, 61 attached t0 bushings 44, 45 and remains in lixed position during rotation of the cylinder.

A silk screen or other thin flexible open-mesh fabric 62 passes from anchoring block 63 on base 41 to a springtensioned roller 64 supported between levers 65, 66. The levers are rotatively mounted on bushings 44, 45 and are further held together by `handle 67.

In making a copy, the intermediate sheet is placed against the original and the composite is smoothly laid against the transparent portion of the cylinder 53 in position for reex exposure and with that portion of the cylinder uppermost, and the handle 67 is then pulled forward and held in that position, with the screen 62 holding the sheets rrnly and smoothly against the surface of the cylinder. Current is supplied to the bulb `49 for the indicated exposure time. The screen is then allowed to be rewound on the roller 64, the sheets are removed, and the cylinder is rotated to place the opaque portion 55 uppermost. The exposed intermediate sheet is separated from the original and placed against a copy-sheet, and the two placed against the cylinder by the same procedure previously used. The visible image is developed rapidly on the copy-sheet. The copy is removed. The lamp 46 may then be extinguished.

It will be appreciated that a blower or other ventilating means may be mounted at one end of the apparatus 40 for more rapidly cooling the exposure station of the cylinder 53 following a copy sequence. Likewise a timer may be included for indicating the exposure time. `In place of the two-part cylinder 53 may be substituted a glass cylinder coated over one-half its circumference with an opaque light-absorbing heat-conductive paint. Various other improvements and additions may be made, e.g. as suggested in connection with FIGURES 1-3, without departing from the spirit of the invention.

A typical copying apparatus made in accordance with the principles of this invention may use a coiled tungsten filament lamp having a length 'of 10 inches and an electrical rating of 1350 watts at 280 volts, preferably with some concentration of filament toward the ends of the lamp, and mounted within a housing having a radius of about 5 inches.

What is claimed is as follows:

1. Copying apparatus for making copies of graphic originals by a process involving light-exposure and heatdevelopment, said device comprising a source of radiant energy suspended adjacent a reflector and between an exposure station and a development station, and means for placing said reflector and said exposure station and development station in relative position for reecting said radiant energy alternately toward said exposure station and said development station respectively.

Z. The copying apparatus of claim 1 wherein said reector is movably suspended with respect to fixed exposure and development stations.

3. The copying apparatus of claim 1 wherein said re- Hector is iixedly suspended with respect to movably mounted exposure and development stations.

4. The copying apparatus of claim 1 wherein an openfaced smooth-surfaced rounded shell comprises said exposure and development stations.

5. The copying apparatus of claim 1 wherein a smoothsurfaced tubular drum comprises said exposure and development stations.

References Cited UNITED STATES PATENTS 2,919,636 1/1960 Kron 355-99 3,056,904 10/1962 Kotz et al. 355-106 3,129,328 4/1964 Wedel 355-106 3,379,112 4/1968 Cranskens 355-110 NORTON ANSHER, Primary Examiner M. D. HARRIS, Assistant Examiner U.S. C1. X.R. 355--117 

